Motor ventilation



Dec. 20, 1949 w. D. ABBOTT MOTOR VENTILATION Filed July 30. 1948INVENTOR Wdrd 4D. Abbott.

WITNESSES: W WM 7Z0.

ATTORNEY Patented Dec. 20, 1949 MOTOR VENTILATIGN Ward 1). Abbott,Orchard Park, N. Y., assignor to Westinghouse Electric {)orporation,East Plttsburgh, Pa a corporation of Pennsylvania.

Application July 30, 1948, Serial lilo. 415% c t'llaims. (or. lib-252)relation to an improvement in the ventilation of a certain type ofcommercial general-purpose motor which has square-sided stator-punchingshaving rounded corners which make contact with a circular cylindricalframe-ring, thereby defining axially extending ventilating-spacesbetween the fiat sides of the stator-'punchings and the frame-ring.

The object of my invention is to provide special duct means forimproving the heat-transfer from the fiat sides of? thestator-=punchings directly to the frame-ring.

With the foregoing and other objects in view, my invention consists inthe structures, combinations, assemblies, parts and methods of designand operation hereinafter described and claimed, and illustrated in theaccompanying drawing, wherein:

Figure 1 is a longitudinal sectional view of a totally enclosed,fan-cooled motor embodying my invention, the section-plane beingindicated at in Fig. 2, and

Fig. 2 is an end view of the motor shown in Fig. 1, with the top halfcut away to show a central transverse sectional view of the top half ofthe motor.

mule my invention is not limited to totally enclosed, fan-cooled motors,being equally applicable to other types of dynamo-electric machines, ithas been illustrated in connection with a totally enclosed, fan-cooledmotor because of the greater urgency of the need for better heattransferconditions in these enclosed motors.

The illustrated motor comprises a stator-memher 3 and a rotor-member 4.The stator-memher 3 comprises a strong, rigid frame-ring 1 0+.

' circular cylindrical shape, which constitutes an imperforateenclosure-ring for the machine. the stator-member also comprise astator-core comprising a rigidly held stack of stator-lamlnations 8, theouter periphery of which is prefrotor-member ll, by an airgap it. Theouter periphery of the rotor-core i3 is provided with a squirrel-cagewinding :55, in the illustrated form of embodiment of my invention, andthe squirrel" cage winding 55 is shown as being cast, with integrallycast fan-blades projecting axially outwardly therefrom, at each end ofthe squirrelcage member. The rotor-core I3 is carried. by a shaft llwhich also constitutes a part of the rotor-member t.

The stator-member 3 of the motor comprises a suitable form ofend-bracket construction for rotatably supporting the shaft and forventi lating the motor, according to the particular type of ventilationwhich is adopted for any particw lar motor. Since the illustrated motoris a totally enclosed, fan-ventilated motor, it has twosets ofend-brackets at each end of the machine, namely inner, imoerforatebrackets which make contact with the ends of the stack ofstator-laminations 8, near the outer periphery thereof, so as to totallyenclose the working parts of the motor. These inner brackets 2&4 carrythe bearings 23 which support the shaft ii. The illustrated motor alsohas outer end-brackets, which are shown in the form of hoods 22, whichmake contact with the ends of the frame-ring l, and extend around overthe inner brackets with a ventilating-space therebetween. Disposedwithin the ventilating-space within the hood 22 at one end of themachine, is an axialflow fan 23 which is carried by the shaft ll of therotor-member, and which extends into the space between that hood 22 andthe inner bracket 26 at that end or the machine, so as to maintain agas-flow, usually air, flowing axially through the four axially disposedventilating-ducts M between the stator-laminations 8 and theframering 1. r

In the particular motor shown, the stack of stator-laminations I is heldin rigid assembly by means of a locking-bar construction 24, disposed ateach of the rounded corners 9 of the erably square, as shown in Fig. 2,with rounded corners 9 which fit within the ins de of the framering I,so as to make contact with said framering at only a few spaced pointsaround the periphery of the core, thereby providing four intermediate,axially disposed ventilating-ducts Ill between the fiat sides H of thestator-laminations 8 and the frame-ring I.

The inner periphery of the stator-laminations 8 carries a stator-windingl2. The inner periphcry or the stator-laminations 8 is separated fromthe outer periphery of the rotor-core l3 of the lamlnations, as moreparticularly described and claimed in an application of Goodwin et al.,Serial No. 690,629, filed August 15, 1946, now Patent No. 2,447,645,patented August 24, 1948.

The illustrated motor also embodies a convertible-frame feature, onepart of which involves a particular construction of the inner brackets20 whereby the core-engaging part of each of these inner brackets is atthe end of a cylindrical bracket-portion 25 which is provided withspaced outwardly extending lugs 28 which serve to properly space andcenter the inner bracket II with respect to the frame-ring land thecorresponding hood 22. 'The convertibleframe construction is aconstruction whereby diflferent kinds of end-brackets (not shown) can besubstituted tor the illustrated end-bracket assembly, so thatdifferently ventilated motortypes can be made, with the same essentialframe and core parts, as more particularly described and claimed in anapplication of Ludwig et 111., Serial No. 690,628, filed August 15,1946.

The motor which has thus far been described in detail is old. Itoperates by a flow of ventilating-air which is forced by the fan 23through each of the four ventilating-ducts it between the outerperiphery of the stator-laminations 8 and the inner periphery of theframe-ring I, so that heat will flow in two principal paths. Oneheatfiow path is directly from the rounded corners 9 of thestator-laminations 8, into the frame-ring l at the four points ofcontact between these corners and the ring; and thence from the ring toboth the outer air and the internally circulated air which flows throughthe axially extending ventilating-doom 0. The other heat-flow path ofthis general type of motor is from the flat sides H of the stack ofstator-laminations 3 directly to the axially flowing ventilating-air inthe four ventilating-ducts l between these fiat sides of the laminationsand the inner periphery of the frame-ring I.

My present invention is concerned with means for providing a directheat-fiowpath from each or the flat sides H of the stator-laminationsdirectly to the frame-ring i, from whence, the heat can be dissipatedeither to the external air or to the axial ventilating-fiow, or by bothmeans. According to my invention, I provide a plurality of duct-members30 which are disposed within the four axially extendingventilating-ducts l0 between the fiat sides I i of thestator-laminations 8 and the inner periphery of the frame-ring 1'. Eachof the duct-members 30 has a completely encompassing, molecularlyintegral wall of heatconducting material, defining anraxially extendingduct 31 within each duct-member 30. By

"molecularly integral, I refer to any construction which is effectivelya one-piece construction, whether welded or brazed into one piece, orcast or extruded in one piece, such one-piece or molecularly integralconstruction being necessary to facilitate the heat-flow. Theseductmembers 30 are of special contour, having a fiat wall 32 which isdisposed in good, broad-surfaced heat-exchanging relation to thefiat-sided outer periphery H of the stator-core 3. Each ductmember 30also has a cylindrically curved wall 33 which is disposed in good,broad-surfaced heat-exchanging relation to the inner periphery of theframe-ring E.

In one form of embodiment of my invention, I first lay, over the flatside H of the stack of perforations, a thin shim 34 of heat-conductingsheet-materiaL which is disposed between the periphery of the stack ofstator-laminations and each of the associated fiat walls 32 of theseveral duct-members 3B, for the purpose of improving the heat-transfercontact with the edges of the stator-laminations 8. This shim 34 is madeof a soft material that will be extruded or cut by high punchings in anunevenly stacked core, thereby spreading the contact over more than justthe high punchings.

Preferably, in practicing my invention, I make the duct-members 3!!smaller than the four axially extending ventilating-ducts it between theflat eluded. Since these special duct-members me:

sides ll of the stator-punchings 8 and the flat ring I. In theillustrated form of embodiment o: my invention, two of theseduct-members 30 an disposed in each of the four axially extendimventilating-ducts HI, the two duct-members 3| being pressed into thepointed portions of thl segmental duct H) which is defined by thestraigh side II of the laminations 8 and the curved Sidl of theframe-ring l, as clearly shown in Fig. 2 In this way, the duct-members30 subdivide thl segmental ducts in into a plurality of axiallyextending ducts, while the walls of the duct-members 30 constituteadditional heat-transfer path: for conducting heat both to the axiallyfiowin ventilating-air and from the stator-lamination: 8 directly to theouter frame I.

Experience has shown that my herein-claims: heat-dissipation means andmethods material]: reduce the running temperatures of the motor: inwhich my special duct-members 30 are inbe made of aluminum or otherrelatively inex' pensive light-weight metal, it will be obvious the; Ihave effected an improvement in efficiency 0 the motor, without any verygreat increase 1: either the cost or the weight of the motor.

While I have illustrated my invention, and described lts method ofapplication, in only a single preferred form of embodiment, and inconnectior with only a single type of motor which has beer chosen forillustration, I wish it to be understooz that my invention issusceptible of considerabh modification, by way of additions, omissions,an: the substitution of equivalents, without departing from theessential spirit of the invention. I desire, therefore, that theappended claims shall be accorded the broadest constructionconsistenwith their language.

I claim as my invention:

1. A dynamo-electric machine comprising 5 stator-member and arotor-member; said statormember having a rigid frame-ring, a stator-concomprising a rigidly held stack of stator-laminations fitting within theinside of the frame-ring said stator-core making contact with theframering at only a few spaced points around the periphery of the core,thereby providing intermediate, axially disposed ventilating-ductsbetween the stator-core and the frame-ring, an: a plurality ofduct-members disposed within saic ventilating-ducts, each duct-memberhaving 2 completely encompassing, molecularly integra wall ofheat-conducting material, defining ar axially extending duct, two wallsof each ductmember being in good, broad-surfaced heat-ex changingrelation to the outer periphery of thr stator-core and the innerperiphery of the framering, respectively; and means for maintaining rgas-flow through said axially extending ducts,

2. The invention as defined in claim 1, in combination with thin shimsof heat-conducting sheet-material disposed between the periphery o: thestack of stator-laminations and the associated walls of the severalduct-members.

3. The invention as defined in claim 1, characterized by eachduct-member filling only a por' tion of one of the axially disposedventilatingducts between the stator-core and the framering.

4. The invention as defined in claim 1, characterized by the outerperiphery of said stack 01 stator-laminations being substantially squarewith rounded corners at the contact-making points with the frame-ring.

5. The invention as defined in claim 1, char- 6 acterized by the outerperiphery of said stack tion of one of the axiallydlsposedtventilatingof stator-laminations being substantially square,ducts between the stator-core and the framewith rounded corners at thecontact-making ring.

points with the frame-ring, in combination with WARD D. ABBOTT. thinshims of heat-conducting sheet-material dis- 5 posed between theperiphery of the stack of stator- REFERENCES CITED laminations and theassociated walls of the sev- The following references are of record inthe eral duct-members. me of this patent:

6. The invention as defined in claim 1, characterized by the outerperiphery of said stack 0t 10 UNITED STATES PATENTS stator-laminationsbeing substantially square, Number Name Date with rounded corners at thecontact-making 7 55 dit June 0 93 points with the frame-ring, andfurther charac- 2,062,470 Mossay 193 terized by each duct-member fillingonly a por-

